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Kater SQL Functions Calendar comparisons

KATER__SAME_WEEKDAY_LAST_WEEK

The measure for the same day of the week, one week earlier.

Family: Calendar comparisons

Syntax

KATER__SAME_WEEKDAY_LAST_WEEK(measure [, by => date] [, coverage => 'matching_elapsed' | 'full_period'])

Arguments

Required

ArgumentDescription
measureThe measure to compare, written bare, without EVAL.

Optional

ArgumentDescription
byThe date axis to compare along, such as KATER__MONTH(orders.order_date). Left out, it is the one date in GROUP BY. An expression.
coverageWhat the earlier period covers when the query filters the date axis. 'matching_elapsed' takes the same dates, moved back. 'full_period' takes whole periods. One of 'matching_elapsed', 'full_period'. It is 'matching_elapsed' when left out.

Returns

A number. The field menu writes the @format of the field it reads beside it, or @format number(2) where that field has none and can have decimals.

Usage notes

  • It works the measure out again over the source rows of the earlier period. It does not read an earlier row of the result, so a period with no row still has a value.
  • The axis is a date at a grain of day.
  • A date filter on the axis needs fixed dates at both ends. A moving end, such as CURRENT_DATE, is refused.
  • For the change, subtract the call from EVAL(measure). For the percent change, give EVAL(measure) and the call to KATER__PERCENT_CHANGE.
  • In a query, declare it with CUSTOM_CALCULATION. As a MEASURE, it needs by.

Example

This Sandbox query reads the sample shop’s orders. The table shows the rows that Kater gave.

SELECT
orders.order_date AS "Order Date",
EVAL(orders.sum__quantity) AS "Units",
CUSTOM_CALCULATION(
'same_weekday_last_week__sum__quantity',
KATER__SAME_WEEKDAY_LAST_WEEK(orders.sum__quantity, by => orders.order_date)
) AS "Units Week Before"
FROM kater_dataset.orders AS orders
WHERE
KATER__IS_BETWEEN(orders.order_date, DATE '2026-09-25', DATE '2026-09-30')
GROUP BY
orders.order_date
ORDER BY
1
Order DateUnitsUnits Week Before
2026-09-25919
2026-09-261835
2026-09-271721
2026-09-281129
2026-09-293611
2026-09-30911

See also